fix: sanitize oversized image payloads

src/agents/tool-images.test.ts

@@ -1,7 +1,7 @@
 import sharp from "sharp";
 import { describe, expect, it } from "vitest";
 
-import { sanitizeContentBlocksImages } from "./tool-images.js";
+import { sanitizeContentBlocksImages, sanitizeImageBlocks } from "./tool-images.js";
 
 describe("tool image sanitizing", () => {
   it("shrinks oversized images to <=5MB", async () => {
@@ -33,6 +33,56 @@ describe("tool image sanitizing", () => {
     expect(image.mimeType).toBe("image/jpeg");
   }, 20_000);
 
+  it("sanitizes image arrays and reports drops", async () => {
+    const width = 2600;
+    const height = 400;
+    const raw = Buffer.alloc(width * height * 3, 0x7f);
+    const png = await sharp(raw, {
+      raw: { width, height, channels: 3 },
+    })
+      .png({ compressionLevel: 9 })
+      .toBuffer();
+
+    const images = [
+      { type: "image" as const, data: png.toString("base64"), mimeType: "image/png" },
+    ];
+    const { images: out, dropped } = await sanitizeImageBlocks(images, "test");
+    expect(dropped).toBe(0);
+    expect(out.length).toBe(1);
+    const meta = await sharp(Buffer.from(out[0].data, "base64")).metadata();
+    expect(meta.width).toBeLessThanOrEqual(2000);
+    expect(meta.height).toBeLessThanOrEqual(2000);
+  }, 20_000);
+
+  it("shrinks images that exceed max dimension even if size is small", async () => {
+    const width = 2600;
+    const height = 400;
+    const raw = Buffer.alloc(width * height * 3, 0x7f);
+    const png = await sharp(raw, {
+      raw: { width, height, channels: 3 },
+    })
+      .png({ compressionLevel: 9 })
+      .toBuffer();
+
+    const blocks = [
+      {
+        type: "image" as const,
+        data: png.toString("base64"),
+        mimeType: "image/png",
+      },
+    ];
+
+    const out = await sanitizeContentBlocksImages(blocks, "test");
+    const image = out.find((b) => b.type === "image");
+    if (!image || image.type !== "image") {
+      throw new Error("expected image block");
+    }
+    const meta = await sharp(Buffer.from(image.data, "base64")).metadata();
+    expect(meta.width).toBeLessThanOrEqual(2000);
+    expect(meta.height).toBeLessThanOrEqual(2000);
+    expect(image.mimeType).toBe("image/jpeg");
+  }, 20_000);
+
   it("corrects mismatched jpeg mimeType", async () => {
     const jpeg = await sharp({
       create: {